Conversion of hydrocarbons with alkali metal-free catalyst comprising silica and amphoteric oxide



Nov. 4, 1947. J. R. BATES 2,429,981

CONVERSION OF HYDROCARBONS WITH ALKALI METAL-FREE CATALYST COMPRISINGSILICA AND AMPHOTERIC OXIDE Filed Dec. 23, 1959 l iNVENTOR JOHN R.BATELS- lawn-44mm ATTORNEY Patented Nov. 4, 1947 CONVERSION OF HYDROCARBONS WITH ALKALI METAL-FREE CATALYST COM- PRISING SILICA ANDAMPHOTERIC OXIDE John R. Bates, Swarthmore, Pa., assignor to HoudryProcess Corporation, Wilmington, Del., a corporation of DelawareApplication December 23, 1939, Serial No. 310,762

7 Claims. 1 The present invention is a continuation-inpart of mycopending application Serial No. 170,648, filed October 23, 1937.

It relates to contact masses, their preparation and use. Moreparticularly, it is concerned with.

contact masses having selected and controlled properties suitable foruse in fluid contactin operations to exert catalytic influence over,enter into, or in any Way assist chemical or physical changes in whichthe fluid participates. It has to do with catalysts derived frommaterials having zeolitic or base exchange properties and particularlythose materials which are prepared by wet methods.

Artificial base exchange bodies prepared, for example, from solublesilicates and other compounds, amphoteric and otherwise, have found wideusage in the treatment of water or for other purposes wherein thebase-exchanging capacity of the zeolite is utilized. Many such zeoliteshave high adsorptive capacity which renders them valuable startingmaterials for the production of catalysts. Catalysts prepared from thesezeolites, however, have often failed to have the expected activity orthe ability to retain it in use especially to promote organic reactions,which leave burnable deposit thereon necessitating periodic regenerationby combustion of said deposit, as for example, in effecting catalyticdecomposition of hydrocarbons, to yield products of the gasoline type.Such processes utilizing these contact materials have failed, from acommercia1 standpoint, to be equal to or better than processes efiectedwith the aid of cheaper and quite satisfactory catalysts comprising orconsisting of suitably prepared naturally occurring or mineralsubstances, such as clays and other ores.

One object of the present invention is to provide synthetic catalystsfor promoting hydrocarbon-conversions characterized by high activity andhigh stability. Another object is to improve hydrocarbon conversionprocesses. Another object is to obtain high yields of gasoline havinghigh anti-knock rating and high stability. Another object is to makeproducts of selected chemical nature with low formation of catalystdeposit. Other objects will be apparent from the detailed descriptionwhich follows.

According to the invention, economical processes for transforminghydrocarbons giving high yields of particularly valuable products resultfrom the use, as catalysts, of plural component synthetic materialsderived from base exchange oxides prepared by wet methods undercontrolled pI-I within the range of 3 to 11 and consisting es- 2sentially of the nuclear components of the base exchange body insubstantially unchanged proportion and molecular relation. Thesecatalysts may contain some alkali metal but its amount must not exceed1% by weight of sodium oxide or its stoichiometric equivalent.

These catalysts are made by base exchanging with a solution containing avolatile or heat unstable cation, a eolite prepared from ingredientscontaining in addition to nuclear components a predetermined andcontrolled amount of one or more suitable anions. The quantity of theselected anion controls both the pH of the zeolite forming reactions andthe extent to which alkali metal may be removed by the base exchangestep. Anions capable of forming weak or strong acids are suitable withthe exception of those containing amphoteric elements. Common anionswellsuited for the purpose of the present invention include 01-, SO3=, SO4=,CO2=, C2H302. The anion may be presented to the reacting ingredients ofthe zeolitic gel, coagulum, or precipitate as an acid and/or as a salt.In some instances, the anion is present in suitable amount in thereacting ingredients of the zeolite as, for example, in combination witha cation, the oxide of which enters into the nonexchangeable or nuclearportion of the zeolite. This is exemplified by certain Zeolites preparedby interreaction of solutions of sodium silicate and certain aluminumsalts, e. g., aluminum sulphate, ammonium alum, aluminum chloride,aluminum acetate. In some cases it is necessary to add an additionalquantity of an anion in order to have the alkali metal present inremovable form. In other cases, there may be no suitable anions in theoriginal reactants whereupon all the anions may be added in a separatesolution. Such is the case when, for example, solutions of sodiumaluminate and sodium silicate comprise the starting materials for thepreparation of a zeolite. The anion-containing compound may then bemixed with the soluble silicate or with the amphoterate, or, after themanner disclosed in my copending application, Serial No. 174,966, filedNovember 1'7, 1937, the anion-containing solution may be added to amixture of solutions containing the nuclear elements of the zeolite andhave the additional'function of coagulating the same. When the anion isdeliberately added as an extra ingredient to the zeolite formingmaterial it is preferably in the form of a volatile or heat unstablecompound, the cation of which is capable of practically complete removalby a simple physical treatment such as heating, such for example, asvolatile inorganic which is neutral or practically neutral.

salts including ammonium chloride, volatile organic salts such, forexample, as methylamine hydrochloride, unstable salts such as ammoniumsulfate, nitrate, and carbonate, or volatile or unstable acids includinghydrochloric acid, formic acid and acetic acid. Ammonium sulphate is thepreferred addition agent. When this compound is added to a sol, forexample, to act as coagulating agent the finished catalyst has higheractivity in hydrocarbon conversions than catalysts obtained fromalkaline reactants and any of the other coagulating or addition agentsgiven above.

When the reacting solutions, including the anion-containing material,for forming a zeolite containing sodium, for example, are soproportioned that the pH of the mixture is below about 11, the sodiumcontent of the zeolite may be reduced to 1% or less and often below .75%by base exchange with the selected cation, even when the original sodiumoxide content of the zeolite is as high as approximately 7 to 9%. Inmost instances, when the pH of the reacting ingredients is about 10 orbelow, the sodium oxide content is easily reduced to 0.5% or below,while pH values below 9 permit reduction of the sodium oxide content toabout 0.2% at which point the accepted methods of analysis becomeinadequate for accu rate determination. This is considered equivalent tovirtual exhaustion of the undesirable component.

The actual removal of sodium or other metallic component or constituentis effected by treating the zeolite with a solution incapable ofdissolving nuclear substances by acid reaction and containing the baseexchanging cation. The latter must be of a volatile or decomposablenature and susceptible of substantially complete removal from thenuclear substances by the application of heat. The solute may be, andpreferably is, a compound which is also of a volatile or heatdecomposable nature, as for example, compounds of ammonium, of aminesand of other organic bases. The operation is simple, comprising onlycontacting the zeolite one or any desired number of times with asolution of the selected compound and may be made at any time afterprecipitation or coagulation, but preferably after drying and/orwashing. A good operation results from the use of a salt Ammoniumchloride is one of the best compounds for such use.

In most instances, no more than six, and, usually, four or fewer,successive dips of the zeolite in the chosen base exchanging solution ofproper concentration are necessary to remove the desired or requiredamount of the non-nuclear component or constituent. The operation isefiiciently and economically conducted when each dip of the precipitateor coagulum is made in approximately one-half of its weight of a baseexchanging solution comprising, for example, a to solution of ammoniumchloride or a solution containing a stoichiometrically equivalent amountof the ammonium or another desirable volatile or unstable cation.Elevated or superatmospheric temperatures tend to increase the speed ofthe base-exchanging process. The quantities and concentrations of thebase-exchanging solutions are not critical, and, as long as a sufiicientamount of the desired cation is present satisfactory results areobtained with relatively larger amounts of more dilute and withrelatively smaller amounts of more concentrated solutions. Likewise thenumber of dips required will usually vary inversely with the relativestrength of the solution. Although successive dipping or batch treatmentproduces the desired result, for reasons of economy, in large scaletreatment continuous countercurrent extraction to equivalent extent isutilized. Also, substantial economies in the quantity of base exchangingcompound are realized when the precipitate or. coagulum is washed freeof excess quantities of the undesirable component or constituent and ofother soluble substances, such as salts. Preferably, this washing isefiected after drying the coagulum or precipitate and with suitablypurified water which is free of the undesirable material.

The product resulting from the base exchanging step is a modifiedzeolite comprising the nucleus of the coagulum or precipitatesubstantially free of the base exchanging component or constituentoriginally held therein and zeolitically holding to the extent of itszeolitic capacity a base exchanged component or constituent susceptibleof substantially complete removal by heat. The base exchangin stepremoves substantially none of the nuclear material. In no instance doesthe nucleus have associated therewith the original base exchangingmaterial in an amount more than that equivalent to 1% by weight ofsodium oxide and preferably contains below three-fourths or evenone-half or less of that amount. It may contain as a zeolitic componentor constituent, as much as approximately 5% by weight of the ammoniumion or radical or an equivalent amount of another volatile or heatunstable cation.

When the ultimate product is to be the original nucleus in substantiallypure form, the modified zeolite is subjected to heat treatment to driveoff its content of volatile or decomposable substance. For this purpose,the modified zeolite is simply heated'to a temperature below that atwhich substantial depreciation of the desired catalytic properties ofthe nucleus takes place and is held at the selected temperature for asuitable and usually short period of time. When the modified zeolitecomprises silica, alumina, and exchangeable ammonium, substantially allthe ammonium is usually ejected when the zeolite is held at atemperature within the range of 700 to 1050 F. for a period of two hoursor less. Higher temperatures may, however, be utilized, and it ischaracteristic of the catalysts embraced within the scope of theinvention that they are exceptionally stable to heat, being capable ofmaintaining high activity for long commercial life involving frequentregenerations at combustion temperatures.

A predetermined and controlled amount of other material, includingmetals and metal oxides may be made a constituent or component of thefinished catalyst. Such material may be inserted into the modifiedzeolite by base exchange in any desired quantity up to its full baseexchange capacity. Inforder to make such contact masses, the modifiedzeolite, preferably in dried and washed form, is immersed one or moretimes in a solution containing cations of the desired metal or metaloxide in proper and regulated concentration. Accurate and rigid controlover the amount of the additional material incorporated within thestructure of the zeolite is attained through regulation of the strengthof solution and of the number of immersions employed, the generaltendencies being toward increased base exchange with higherconcentrations and greater number of immersions. In this manner, anymetallic element in the first to the eighth groups of the periodic tablefor example, wermnfiMfl Cr,

V, W, Li, Cs, Rb, Al, Ca, Sr, Ti, Mo, Mg, may be-' come a constituent ofthe end product. Heat treatment of the modified zeolite followingintroduction thereinto of a metal constituent in zeolitic substitutionfor any desired portion of its content of volatile ordecomposablematerial may thus produce a contact mass made up of thedesired constituents or components in closely regulated proportionateamounts and substantially free of the original base exchangingcomponent.

Gels prepared by coagulation of sols with a solution containing avolatile cation are of peculiar importance among the gelatinousmaterials suitable as starting materials for active and stablecatalysts. These gels or coagulums are always alkaline when produced andare the only ones having pH values above about 8, as within the range of9 to 11 which are susceptible of treatment to yield catalysts of optimumactivity and stability. Full advantage in these respects is obtainedfrom other gels, as exemplified by products obtained by interreaction ofa soluble silicate and a salt of an amphoteric metal, or by coagulationwith acid of a mixture or sol of the silicate and alkaline amphotericsolutions, when the gels are prepared at lower pH conditions, usuallybelow 8 and preferably below 7, as within the range of 4 to about '7.

The invention is not limited to catalysts derived from two componentnuclei. On the contrary, the stability, selective activity, or both, ofsynthetic catalysts may be further improved by inclusion of one or moreadditional selected components in the nucleus of the base exchange body.The presence of a desired and usually small quantity of thoria,beryllia, for example, intimately associated with silica and alumina ina base exchanging nucleus, or a difiicultly reducible oxide of a metalof Group IV of the periodic table, improves the stability of theresulting catalyst for promoting production of gasolines and the likefrom naphthas and higher boiling hydrocarbons. The effect of additionalnuclear components becomespronounced when made a part of the nucleusunder pH conditions of about 8 or below and preferably '7 or less.

charging stocks ranging from crude distillation residues to naphthashaving boiling range characteristics of gasoline and including crackedand other naphthas of high acid heat, gasolines made according to theinvention have acid heats of 60 F. and below and usually 40 F. or below.

The splitting reactions are preferably conducted in vapor phase. Formost charging stocks catalyst temperatures within the range of 700 to1050 F. are suitable, temperatures within the lower portions of therange, as up to 950 F. being usually employed for the transformation ofhigh boiling hydrocarbons, and temperatures within the upper portion ofthe range, or 800 F. and higher, for kerosenes and other naphthas. It ispreferable to employ comparatively low pressures, as from atmospheric upto 150 or 200 lbs. per sq. in. gauge. Pressures of about 30 lbs. per sq.in. gauge and up are of some advantage in transforming the morerefractory naphthas and similar charging stocks, but it is preferred touse pressures below about 100 lbs. per sq. in. for

. transformation of higher boiling hydrocarbons In addition tomaintaining a high activity after many months of commercial scaleoperaton involving as many as or more than 20 regenerations per day byburning of combustible deposit formed thereon, catalysts characteristicof the invention selectively promote formation of desired product withlittle tendency to form and accumulate contaminating deposit.

Over and above these advantages, which directly provide improved andmore economical plant operation, these catalysts, despite being highlyactive in promoting splitting and kindred decomposition reactions,possess highly selective activity which direct the course ofdecomposition reactions toward products possessing a high degree ofstability and marked anti-detonating characteristics. Motor fuelsproduced by their use under decomposition conditions, even withoutfurther purification, characteristically have high resistance tooxidation and other deteriorating influences encountered in storage anduse, as measured, for example, by oxygen bomb induction periods,accelerated gum determinations, color stability tests, etc. In fact,these motor fuels are unique among those resulting from splitting andother decomposition reactions in that they possess the peculiar type ofstability required of modern aviation gasolines and currently indicatedby standardized acid heat or bromine number determinations. Utilizing awidevariety of such as gas oils and bottoms fractions.

Example 1 A silica-alumina zeolite was prepared from a solution ofsodium silicate comprising about 900 parts by weight of a commercialwater glass having a specific gravity of approximately 1.4 and about2500 parts by weight of water by mixing it with an equal volume of asolution containing about 320 parts by weight of commercial ammoniumalum and approximately 2800 parts by weight of water. Within a shorttime a gelatinous precipitate formed. This precipitate having a pH ofthe order of 8 was then dried and washed with purified water untilpractically free of sulphates. Upon analysis the resulting solid wasfound to comprise about 84.3% S102, 11.7% A1203, and 4% NazO (anhydrousbasis). It was then immersed for 30 minutes in one half its weight of a10% solution of ammonium chloride maintained'at a temperature of theorder of F., removed from the solution and washed with purified water.The immersion and succeeding washing steps were repeated three times andthe resulting ammonium zeolite comprising the silicaalumina nucleus andapproximately 2.3% by weight of the ammonium radical was divided intotwo portions.

One portion was heated to approximately 1050 F. and maintained at thattemperature for about 2 hours, after which it was cooled and a samplesubjected to chemical analysis. This material, found to consist ofapproximately 87.6% $102, 12.1% A1203, and 0.3% Na2O (anhydrous basis),was used as catalyst in a continuous process for the transformation ofCoastal gas oil having the approximate boiling range of 420 to 720 F.into 410 F. end point motor fuel involving repeated cycles oftransformation periods of about 15 minutes duration alternating withregeneration periods when the coke like by-products of thetransformation reaction were burned off at temperatures in the range of800 F. to 1050" F. During the on-stream periods, the catalyst wasmaintained at about 810 F. while the charge was fed to it atsubstantially atmospheric pressure and at the rate of about 1.25:1(volumes of charge,

liquid basis, to each Volume of catalyst per hour). The yield of thefractionated gasoline, which had an octane rating of about 78, copperdish gum of about 3 mg. per 100 00., an oxygen bomb induction period ofmore than 10 hours, and an acid heat below 40 F., was found to be about40% by volume of the charge. The coky deposit, averaging about 1.5% byWeight of the catalysts, was substantially completely removed in 10minute burning periods.

The second portion was treated to prepare contact mass of the typedisclosed and claimed in U. S. Patent No. 2,078,951, issued to Eugene J.Houdry on May 4, 1937, and containing about 0.75% Mn. To this end, itwas immersed for 30 minutes in about twice its weight of a solutioncontaining approximately 0.85 mol of MnSO4 per liter and maintained at atemperature of the order of 180 F. The resulting zeolite containingmanganese was washed until practically free of sulphates, subjected to aheat treatment similar to that described for the first portion of theammonium zeolite. A sample was analyzed for manganese content, which wasfound to be about 0.78%. This material was used in a hydrocarbontransforming operation similar to that described above and producedmotor fuel of about the same quality and quantity. During such use itwas regenerated rapidly and substantially completely at temperatures inthe range of 900 to 1000 F.

Example 2 About 2500 parts by weight of a solution of sodium silicatehaving a specific gravity of about 1.4 was diluted with about 8200 partsby weight of water. This solution was mixed, in the weight ratio of 560to 104 with a solution of sodium aluminate of approximately half thestrength of that employed in that example. To this mixture there wasadded about 60 parts by weight of concentrated hydrochloric acid,immediately after which addition a gel was formed. This gel, which had apH of about 4, after being dried and washed free of chlorides was foundto contain about 2% by weight of sodium oxide. This zeolite Was thengiven three dips in 5% ammonium chloride solution and a subsequent heattreatment at about 1000 F. for about 2 hours. The resulting prod- 'uctwas highly porous and was an active catalyst in the production of highanti-knock motor fuels from higher boiling hydrocarbons, or fromnaphthas of lower anti-knock rating. The composition of this product Wasdetermined by chemical analysis and c'ompared'with the analysis of thedried and washed gel. The base exchanged product was thus found to be,within the limits of experimental error, ofthe same composition as thenucleus of the gel and contained, in addition, approximately only 0.2%of sodium oxide.

Example 3 A solution of commercial sodium silicate containing about 11.8mols of silica was mixed With a solution of commercial sodium aluminatecontaining approximately 1 mol of alumina to form a sol, the solutionsbeing of such concentration as to be capable of yielding anall-embracing gel. To this sol, before precipitation or gellationcoagulation had taken place therein, there was added a solution ofammonium sulphate in an amount about stoichiometrically equivalent tothat sodium oxide content of the sol. The coagulum of about 9.6 pH whichwas then formed was dried at about 200 F. and washed practical- 1y freeof sulphate. It was then treated with a solution of ammonium chlorideuntil its residual sodium content had been reduced to approximately0.2%. The resulting ammonium zeolite was then washed free of chloride,dried and given an activity adjustment treatment in accordance with mycopending application Serial No. 289,915, filed August 12, 1939, bysubjecting at temperature of about 1400 F. for 10 hours in an atmospherecomprising 95% air and 5% steam to yield a finished catalyst consistingessentially of substantially pure silica-and alumina.

A portion of this catalyst was utilized to transform a naphtha obtainedfrom a Coastal crude having a boiling range of about 154-464 F. and anoctane rating of about 57. In this operation the naphtha was fed to thecatalyst at a rate of about 2.25:1, (volumes of charge, liquid basis, toeach volume of catalyst per hour) under pressure of the order of 50 lbs.per sq. in. gauge for an operating period of about 10 minutes whilemaintaining the catalyst at a temperature of about 860 F. A portion ofthe products issuing from the catalyst was fractionated and condensed toyield motor gasoline of about 400 F. end point.

This motor gasoline, upon test, had Saybolt color of 30, acceleratedgum, Navy method, of 0.8 mg., oxygen bomb induction period of more than10 hours, sulphur content of 0.01%, and 00- tane, C. F. R. motor method,of 76. Addition of 3 cc. tetraethyl lead to a gallon of this gasolineraised its octane to about 89. The yield of the above described gasolinewas about 82% by volume of the charging stock. A clean higher boilingfraction valuable for use as domestic distillate fuel or as light gasoil comprising about 9% by volume of the charge and having a boilingrange of approximately EO-694 F. was simultaneously produced. Thecoke-like deposit which remained on the catalyst was about 6 grams perliter of catalyst and equivalent to less than 1% of its weight. I

Another portion of the products leaving the catalyst was fractionated toyield an aviation gasoline of about 96 to 322 F. boiling range. Thisproduct had substantially the same oxygen bomb stability and low sulphurand gum content of the above described motor gasoline, an octane ofapproximately 78 which was easily raised to about 91 by the addition of3 cc. of tetraethyl lead per gallon. In addition, this product had anacid heat substantially below 15 F. The yield of this aviation fuel wasabout 62% by volume of the charging stock.

Another portion of this catalyst was utilized to promote transformationof a gas oil obtained from Coastal crude and having an A. P. I, gravityof about 30 and a boiling range of about 420-735 F. This charge stockwas fed to the catalyst at the rate of about 1:1 (volumes of charge,liquid basis, to each volume of catalyst per hour), under pressure ofthe order of 7 lbs. per sq. in. gauge for an operation period of about10 minutes during which the catalyst was maintained at approximately 790F. Fractionation of the vapors issuing from the catalyst yielded a motorgasoline of approximately 410 F. end point having a Saybolt color of 30,a copper dish gum of 3, an oxygen bomb induction period of more than 10hours, sulphur content of 0.01% and an octane rating of (C. F. R. M.M.). The yield of this gasoline was somewhat more than 55% by volume ofthe charge. There was produced with it high boiling material with an endpoint of approximately 720 F. which Was clean and suitable R w-means Nfor use as clean distillate domestic fuels or as light gas oil. Itamounted to about 35% by volume of the fresh charge. Accumulated on thecontact mass was coke-like deposit amounting to less than 9 grams perliter of catalyst and equivalent to about 1.4% of its weight.

The small quantity of deposit remaining on the catalyst in each of theabove operations was easily removed by combustion at temperatures notexceeding 1050 F. in burning periods of about 10 minutes duration.

Example 4 A substantially pure silica-alumina catalyst madesubstantially as disclosed in Example 3 was utilizer to reform astraight run naphtha from West Texas crude, having a boiling range ofabout 110 to 414 F., sulphur content ofapproximately 0.17%, octanerating of about 51 (C. F. R. M. M.) which was raised only to about 54upon the addition of 1 cc. of tetraethyl lead per gallon. This chargestock Was fed to the catalyst at a rate of the order of 1:1 (volumes ofcharge, liquid basis, to each volume of catalyst per hour), underpressure of approximately 50 lbs. per sq. in. gauge and temperature inthe neighborhood of 810 F. for an operating period of 10 minutes. Uponfractionation of the transformed vapors, condensation of the overheadand separation of fixed gas therefrom, condensed gasoline having an endpoint of about 390 F. and amounting to approximately 90% of the volumeof the charge was obtained. This product had a Saybolt color of about30, copper dish gum of about 2 mg, oxygen bomb induction period of morethan 10 hours and sulphur content of approximately 0.01%. Its octanerating, determined by the C. F. R. Motor method, was approximately 70and was raised to about 80 by the addition of 1 cc. of .tetraethyl leadper gallon. The extreme stability of this product is further emphasizedby the fact that it had an acid heat of less than 10 F. The coke depositon the catalyst during this operation was equivalent to less than 0.3%by weight of the catalyst or less than 2 grams per liter of catalyst.

Example 5 A gel containi g silica and alum i n a in the molar ration ofapproximately I? :T w'as prepared by mixing a solution of commercialsodium silicate with a solution of commercial aluminum sulfate andsuflicient concentrated sulfuric acid to yield a gel having a pH valueof the order of 6. After filtering, it was treated with ammoniumchloride solution until its content of alkali metal was reduced to below0.5% by weight of sodium oxide. After again washing, this material washeat treated at about 1050 F. for about 2 hours. The finished catalystwas then utilized to promote transformation of an East Texas gas oilhaving a boiling range of 420 to 720 F. This gas oil was fed in vaporform to the catalyst at a rate of about 1.5:1 (volumes of charge, liquidbasis, to each volume of catalyst per hour) for an operating period ofapproximately minutes while maintaining the catalyst at about 785 F.Upon fractionation, the products of this operation were found to containa quantity of 400 F. end point gasoline equivalent to about 50% byvolume of the charging stock. This gasoline had an octane rating ofabout 80 (C. F. R. Motor method), acid heat of about 40 F., copper dishgum substantially below 10 mg. and an oxygen induction period over 10hours. A portion of the catalyst was analyzed and. the burnable depositon it found 10 to be approximately 1.8% by weight or about 12 grams perliter. This deposit was substantially completely removed in a burningperiod of about 10 minutes, during which time the maximlum catalysttemperature was maintained below 1 00 F.

Example 6 A three component base exchange body containing silica,zirconia and alumina in the approximate molar ratio of 15:0.9:1 wasprepared as follows. About 22.5 kilograms of a solution of commercialsodium silicat was mixed with approximately 3.5 liters of ammoniumhydroxide solution having a specific gravity of 0.9. To this mixturethere was added a second solution made up of approximately 3.5 kilogramsof commercial aluminum sulfate mixed with about 2 kilograms of zirconiumsulfate. Within a minute an all em bracing gel having a pH value ofabout 5.? set up. This gel was dried, washed and treated with anammonium chloride solution until the total sodium oxide content wasreduced to below 0.5%. This product was divided into two portions.

One portion was heat treated at about 1050 F. for two hours and wasutilized to promote gasoline formation from the same gas oil used inExample 5 and under substantially the same reaction conditions. Thefractionated 400 F. end point gasoline obtained from the reactionproducts was found to amount to approximately 52% by volume of the gasoil charge. Upon analysis, the coke-like deposit on the catalyst wasfound to be less than 1.9% by weight or approximately 13 grams per literand was removed Within a 10 minute burning period conducted at maximumtemperature of 1100 F. Upon extensive use this catalyst maintained itsability to form high yields of gasoline product, but its tendency toaccumulate coky deposit decreased.

The other portion of this catalyst was subjected to heat treatment atabout 1400 F. for 2 hours. When used in a process for producing 400 F.end point gasoline utilizing the same charging stock and substantiallythe same operating conditions as for the first portion of the catalyst,it was found that substantially the same quantity of gasoline productwas obtained. The catalyst deposit, however, was found to beapproximately 1% by weight or about '7 grams per liter.

The gasoline recovered in both the above runs had octane ratings inexcess of '76 (C. F. R. Motor method). Each gasoline had an acid heatvalue below 60 F. along with low copper dish gums and long oxygen bombinduction periods.

A typical illustration of the effectiveness of this catalyst inpromoting transformation of low octane napthas into high octane productis as follows. A heavy naphtha having a boiling range of the order of280 to 450 F. and an octane rating of about 35 and obtained from EastTexas crude was fed to the second portion of the catalyst at the rate ofabout 1.25:1 (volumes of charge. liquid basis, to each volume ofcatalyst per hour) under pressure of the order of 50 lbs. 'per sq. ingauge for a run of 20 minutes duration during which the catalyst wasmaintained at about a temperature of 820 F. The 400 F. end pointgasoline separated by fractionation and condensation from the vaporsissuing from the reaction zone was found to be equivalent to about 60%by volume of the fresh charge. Upon analysis, this gasoline had anoctane rating of about '10 and the color and stability characteristicstypically result from practice of the invention. The coky deposit on 11the catalyst was of the order of 0.8% of its weight or about 5.5 gramsper liter. This deposit was easily removable in a 10 minute burningperiod.

Example 7 A multi-component synthetic catalyst containing silica,aluminaand-beryllia in the approximate molarr'atio of 17;1;0.5 wasprepared in the following manner. A solution containing '70 parts byweight of beryllium sulfate, about 250 parts by weight of aluminumsulfate and of the order of 40 parts of concentrated sulfuric acid wasmixed with a solution containing about 1450 parts by weight ofcommercial sodium silicate. The resulting gel, having a pH of the orderof 5, was dried, washed and treated with ammonium chloride solutionuntil its total sodium oxide content was reduced to below 0.5% byweight. The treated material, after washing and heat treatment attemperature of the order of 1050 F. for 2 hours, was utilized to promotetransformation into antiknock motor fuel of the same gas oil that wasemployed in Examples 5 and 6, the conditions of run being substantiallythe same as described in those examples. The fractionated 400 F. endpoint gasoline resulting from this operation was found to amount toabout 42% by volume of the gas oil charge and had an octane rating inexcess of 7 5 (C. F. R. Motor method) along with the high stability,including acid heat below 60 E, which characteristically results fromuse of the invention. The coky deposit on the catalyst amounted toapproximately .8% of it by weight or of the order of 5.5 grams per literand was easily removed in a burning period at least as short as theon-stream or run period.

Example 8 An active heat stable and regenerative catalyst consistingessentially of substantially pure silica, zirconia and beryllia in theapproximatem'oiar ratio of 15:1:0.9 was prepared. To obtain thismaterial an ammoniacal solution containing approximately 1700 parts byweight of commercial sodium, silicate was mixed with a solutioncontaining about 270 parts by weight of zirconium sulfate and 98 partsby weight of beryllium sulfate and of the order of 120 parts by weightof ammonium sulfate. In about half a minute an opalescent gel, having apH value of the order of 6.4, was formed. This gel was filtered, dried,washed and treated with a solution of ammonium chloride until its totalsodium oxide content was reduced to below 0.5% by Weight. After againwashing, this material was heat treated for about 2 hours at controlledtemperature of the order of 1100 F. and was then utilized undersubstantially the same operating conditions to promote transformation ofthe same gas oil employed in Examples 5, 6 and '7. The yield of 400 F.end point gasoline was approximately 40% by volume of the fresh charge.This gasoline had the highly desirable characteristics including highoctane rating in excess of '70 (C. F. R. Motor method) and the highdegree of stability including long oxygen bomb induction periods and lowacid heat which characteristically result from practice of theinvention. The coky deposit remaining on the catalyst was less than 0.8%of it by weight or approximately 4.5 grams per liter and was easilyremoved in a 10 minute burning period conducted at low temperaturesregulated not to exceed 1050 F.

Each of the catalysts described in the foregoing examples maintainedhigh selective activity in promoting formation of stable and anti-knockmotor fuels for long periods of continuous use under commercialoperating conditions.

Although each of these catalysts contained silica, the invention is notlimited solely to silicious materials. Other combinations of intimatelyassociated oxideswhich have high activity and high stability in theproduction of high anti-knock motor fuels by splitting reactions includenuclei of base exchange material comprising intimately associatedcombinations of zirconia and alumina, zirconia and beryllia, berylliaand alumina, thoria and alumina, etc., prepared by coprecipitation orother reaction conducted in the wet under controlled pH conditions,preferably not in excess of about 8. From the viewpoint of cost of thecatalyst, however, it is preferable to use silicious materials, and, insome instances, the presence of silica in the nucleus appears tofavorably affect both the activity and stability characteristics of thecatalyst. The preferred silicious catalysts are those in which thesilica predominates, at least 4 mols of silica, for example, beingpresent in the nucleus for each mol of other nuclear oxide. Very highstability and activity are obtained when at least 10, say 10 to 25 molsof silica are present for each mol of any other one oxidic constituentof the nucleus.

In order to facilitate regeneration it is preferable that the catalystbe presented to the reactants in the form of grains or shaped pieces ofsubstantially uniform size and shape. To this end, the catalytic gel maybe molded into cylinders, pellets or any other desirable shape at anydesired stage of their manufacture or treatment. In the interest ofutilizing, unimpaired, the activity and stability of the syntheticcatalytic prodnot it is preferred that the molding operation beconducted without the aid of extraneous bindin materials containing orcomprising sodium or other alkali metal. One molding method which avoidsthe use of extraneous binders is that disclosed in United States PatentNo. 2,146,718 to George R, Bond, Jr., dated February 14, 1939.

The high anti-knock rating, stability and other value properties ofproducts of the invention are probably due to the fact that theselective catalysis promotes formation of stable branch chain 'paraffinsto the exclusion, or substantially so, of

reactions which terminate with the formation of olefines or whichconvert straight chains to ring compounds. The products, whether derivedfrom naphthenic or parafiinic base starting materials are predominantlyparaffinic with the branched chain paraifins preponderating, often inmolar ratios as high as or higher than 4:1 over the straightfchaincompounds; in fact, their content of branch chain parafiins usuallyexceeds their content of any other type of hydrocarbon, and, in someinstances, exceeds the total quantity of all other types ofhydrocarbons, found in the products. Their content of olefines isgenerally below 10 mol percent, and in many cases is as low as 2 to 4%.I

In the aliphatic hydrocarbonsnormally occurring in gasoline, say thosehaving from 5 to 12 carbon atoms, there are about 650 possible paraffinsas against over 3800 olefins. Therefore, the fact that but a verylimited quantity of olefins is formed limits to a greatly reduced numberthe components of gasoline made according to the invention. Theresulting mixture of hydrocarbons is comparatively simple, particularlyin pol tions of the gasoline boiling below about 212 F. and becomes evensimpler in the portions boiling at or below 160 F. This simplicity ofcomposition makes possible the separation by fractionation from productsof the invention of selected material having valuable properties. Forexample, the hydrocarbon iso-pentane (2-methyl-butane) boiling at 80 F.is the only parafiin component in the gasoline boiling between 40 and 95F. and can easily be segregated in substantially pure form in a fractioncontaining such a small quantity of olefines (less than 5%) that thelatter can easily be removed, as by acid treatment, with no more thanslight loss. Neo hexane (2,2 dimethyl butane) having an octane rating of94 (C. F. R. Motor method) and having a lead susceptibility superior toiso-octane is another stable hydrocarbon that may be separated in afraction containing minor quantities, if any, of substances whichdetract from its desired properties as motor fuel or as an addition orblending agent to produce premium quality and especially aviation fuels.The parafiins boiling nearest this compound, whose boiling point is 122F., are normal pentane, boiling at 97 F., having an octane rating of 64,and 2,3 dimethyl butane boiling at 136 F. having an octane of 95, and 2methyl pentane, whose boiling point is 60 C. and octane rating 73.Hence, it is relatively simple to obtain a stable fraction containingone or more highly knock resistant hydrocarbons for addition material inpreparing fuels having octane ratings of 90 or above. The preponderanceof iso-paraffins over all other types of aliphatic hydrocarbons providesfor commercially attractive yields of selected fractions containing theabove described hydrocarbons or other desired iso-paraffins.

When the charging stock contains refractory sulphur components, suchcomponents are converted into easily removable form, the resultingstable motor fuel often being capable of meeting market specificationsfor sulphur content and of passing accepted corrosion tests withoutbeing subjected to further purification, except possibly a suitabletreatment to remove traces of hydrogen sulphide, for example, a lightcaustic wash. In addition, when the charge subjected to the selectivesplitting action of the catalyst is a naphtha, the resulting producthaving low acid heat and improved octane rating is more responsive thanthe charge to addition agents such as tetraethyl lead.

The accompanying drawing shows a schematic the onstream and regenerationphases of the cycle may be maintained with the aid of an extraneous heatexchange medium, for example after the manner disclosed in U. S. Patent2,078,947, issued May 4, 1937, to E. J. Houdry et al., in the copendingapplication of E. J. Houdry and T. B. Prickett, Serial No. 261,728,filed March 14, 1939 (now U. S. Patent 2,283,208, of May 19, 1942), orin my copending application Serial No, 308,193, filed December 8, 1939(now U. S. Patent 2,273,826 of February 24, 1942). By preference, theregenerating medium, supplied to the battery by line D and valvedbranches D1, is maintained under superatmospheric pressure which may beup to say 150 lbs. per sq. in gauge, for example, after the manner setforth in U. S. Patent 2,167,698, issued to R. S. Vose on August 1, 1939,or in U. S. Patent 2,167,655, issued to E. J. Houdry et al. on the samedate. Spent regenerating medium issues from the converters intodischarge line J by way of valved branches J1. As indicated by thespecific examples, the low formation of deposit promoted by thesynthetic catalysts provides for short burning periods.

I claim as my invention:

1. In the catalytic transformation of hydrocarbons to yielddecomposition products, the process of subjecting hydrocarbon chargingstock at reaction temperature to the action of a substantially puresynthetic blend of silica and alumina, obtained by base exchanging a drysilica-alumina zeolite produced by drying hydrous coprecipitate ofsilica and alumina containing alkali metal with a solution of a saltselected from the group ammonium salts and amino salts until the alkalimetal content of said zeolite is practically completely removed followedby introduction of a non-volatile cation into said zeolite by baseexchange and by heat treatment of the base exchanged zeolite at hightemperature to drive off residual ammonium or amino cation.

2. In the transformation oil-hydrocarbon fractions containing componentshigher boiling than gasoline to yield products of the gasoline type, thesteps of feeding such as hydrocarbon fraction under conditions suitablefor effecting splitting reactions over a synthetic catalyst preparedfrom a synthetic base exchange body containing silica and an amphotericoxide as nuclear components and precipitated under controlled pHconditions Within the range of 8 to 11 by coagufiow diagram of one typeof operation that ma n be employed in practicing the invention. In orderto provide continuous flow of reactants to and of reaction products froma plant, a plurality or battery of converters of any suitable type, asindicated, for example, at A in the accompanying drawing, is preferablyemployed; each utilized alternately on stream and in regeneration andoperated in coordination or in cycle so that the stream of reactantspreheated in a suitable heater B and supplied to the battery by line Cselectively connected to converters A by valved branches C1 may betransferred from one converter at the end of an operating period thereinto another converter which" has completed the regeneration phase of thealternating operation. The products of conversion discharging into lineE by the proper valved branch E1 may be subjected to fractionation infractionator F to provide a distillate, gasoline, for example, withdrawnby line G and a higher boiling fraction which flows through withdrawalline H. Desired converter temperatures during either or both of lationof a mixture of solutions of a soluble silicate and an alkali metalamphoterate with a coagulating solution containing ammonium sulfate,said catalyst consisting essentially of said nuclear componentssubstantially free of alkali metal originally associated therewith.

3. In promoting hydrocarbon reactions, the process of preparing azeolite from reactant solutions containing silica, an amphoteric metaland an anion formed from a non-amphoteric element so proportioned thatthe resulting gel has a pH value below 11, drying said gel to produce adried zeolite, treating the latter with a solution of a salt containinga volatile or decomposable cation until substantially all the alkalimetal content of the zeolite i removed, introducing a predetermined andcontrolled amount of an active metal into the treated zeolite by baseexchanging a portion only of the substituted volatile or unstable cationfor said active metal, subjecting the resulting base exchanged zeoliteto heat treatment at temperature in excess of 700 F. to drive offsubstantially all the remaining volatile or unstable cation, andthereafter feeding to said zeolite in washed condition and heated todecomposition temperature higher boiling hydrocarbons to convert thelatter into lower boiling decomposition products.

4. The process of transforming naphthas to produce a stable motor fuelof improved antiknock rating comprising the step of contacting thenaphtha charge under dehydrogenation conditions with a, catalystconsisting essentially of substantially pure and calcined nuclearmaterial derived from a precipitated silica- LEM zeolite by drying theprecipitated zeolite and subsequently removing substantially allnon-nuclear components from the dried zeolite.

5. The process of producing gasoline from ordinarily liquidhydrocarboncharge comprising contacting such a hydrocarbon chargingstock under cracking conditions with a contact mass consistingessentially of silica and alumina, prepared by drying a hydrouscomposite of silica, alumina and alkali metal 'oxide, substituting a,cation selected from the group consisting of ammonium and amines forsubstantially all'of said alkali metal oxide in said dried composite,and subsequently calcining the composite'to drive off said cation.

6. In the transformation of hydrocarbon fractions containing componentshigher boiling than gasoline to yield products of the gasoline type, thesteps of feeding such a, hydrocarbon fraction under conditions'suitablefor effecting splitting reactions over a synthetic catalyst preparedfrom a synthetic base exchange'body containing silica and an amphotericoxide as nuclear components and precipitated under controlled'pHconditions within the range of 8 to 11 by coagulation of a mixture ofsolutions of a soluble silicate and an alkali metal amphoterate with acoagulating solution containing" a salt of a weak base which reacts withthe alkali metal content of said mixture to form a weak base and a salt,said catalyst consisting essentially of said nuclear componentssubstantially free of alkali metal originally associated therewith.

7. The hydrocarbon conversion process for the production of normallyliquid, low boiling hydrocarbons, which comprises introducing a,hydrocarbon charge stock in vapor phase under cracking conditions intocontact with a catalyst containing a coprecipitate consistingessentially of silica and alumina which has been substantially freed ofbase exchangeably held material by base exchanging ammonium ion for baseexchangeably held material and by calcination to free the coprecipitateof ammonia, said base exchange being effected in the dried state of thecomposite.

JOHN R. BATES.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,728,732 Jaeger Sept. 17, 19291,782,353 Jaeger et al Nov. 18, 1930 1,840,450 Jaeger et a1 Jan, 12,19321,935,176 Connolly Nov. 14, 1933 2,137,492 Hyman Nov. 22, 1938 2,124,583Morrell July 26, 1938 2,154,820 Ocon Ap 'r. 19, 1939 2,212,035 Morrellet a1. Aug: 20, 1940 2,214,455 Eglofl et a1. Sept, 10, 1940 2,229,353Thomas et al.; Jan. 21, 1941 2,141,185 Houdry Dec, 27, 1938 2,146,718Bond, Jr. Feb.;14, 1939 2,197,007 Pew, Jr Apr."16, 1940 2,206,921Schulze July 9, 1940 FOREIGN PATENTS Number Country ljate 270,314 GreatBritain Q May 2, 1928 270,704 GreatBritain July30, 1928 484,368 GreatBritain May,4, 1938 504,614 Great Britain Apr."24,,1939 515,309 "Great:Britain L 'De' c 1; 1939 820,917

' France "Aug; 9,1937

